Comment by dota_fanatic | Hacker News Reader

Comment by dota_fanatic | Hacker News Reader

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The only thing I can recommend that's helped me significantly in a rigorous way is tracking HRV overnight (heart rate variability). This is an objective indirect measure of HPA axis activity (parasympathetic vs sympathetic nervous systems). Having that data to form a feedback loop is priceless in helping you determine what things you're doing in the day that is actually having an effect on your stress levels one way or the other. As I'm sure you can imagine, my best sleep is on nights when my HRV is high. I no longer drink alcohol or work on software after 7PM in general after seeing just how much those activities would wreck my body's ability to sleep well.

I use an Oura ring for this but I bet there are cheaper methods, perhaps with a heart rate chest strap, though there's an additional bonus with the ring in that it tracks sleep phases as well.*

*to some degree of accuracy (~66%?) I use it directionally only since the values have big error bars.

> Having that data to form a feedback loop is priceless

I'm surprised to hear this, although I'm glad it works for you.

I wear an Apple Watch Series 3 night and day, which reports HRV. I've found it to be pretty difficult to draw conclusions from since the measurement stays pretty much the same even when significantly changing lifestyle/habits. Over the past year I have went pure vegan (went down 15% body weight), went from exercising 0 days a week to 6x 1 hour high intensity, went from chronically sleep deprived to 7-8 hours / night, and HRV has been exactly the same.

Perhaps the accuracy of the apple watch isn't so great compared to what you're using. My measurement tends to fluctuate between 25ms - 40ms throughout the month with an average of 30ms over the entire month for the past year, despite the dramatic lifestyle changes mentioned above.

I've noticed Apple Watch's VO2 max measurements are also -very- unreliable. Mine has decreased 25% in the past year despite being at a dramatically higher cardio fitness level.

Curious if anyone else with an Apple Watch has had a similar experience with these measurements. I really like the idea of using them as a feedback loop, which is partly why I wear an apple watch to begin with, but hasn't quite panned out.

That is interesting. I haven't used any of the Apple watches so I can't speak to the effectiveness of its HRV calculations for me. One of the Oura C-level guys spoke in a podcast that doing those kinds of calculations isn't as reliable because of differences in vascularity / fit on the wrist vs a finger but who knows how true that is. Maybe it's true only for the existing monitoring tech?

I've seen my average vary from 10-50 and HRV max from 50-140 depending on sickness, exercise routine, hydration, drug use, etc. The quality of that average is interesting to observe as well, ie two nights' average of 40 can look very different depending on the peaks and valleys.

It is challenging though to suss out what effects various things have. It requires a whole lot of normality in my lifestyle so as to limit the number of variables as best I can.

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